Near-infrared optical sensors based on single-walled carbon nanotubes

Research areas:
  • Uncategorized
Year: 2005
Type of Publication: Article
  • P. W. Barone, D. A. Heller S. Baik
Journal: Nature Materials Volume: 4
Number: 1 Pages: 86-U16
Month: JAN 2005
PT: J; TC: 373; UT: WOS:000226113600022
Molecular detection using near-infrared light between 0.9 and 1.3 eV has important biomedical applications because of greater tissue penetration and reduced autofluorescent background in thick tissue or whole-blood media. Carbon nanotubes have a tunable near-infrared emission that responds to changes in the local dielectric function but remains stable to permanent photobleaching. In this work, we report the synthesis and successful testing of solution-phase, near-infrared sensors, with beta-D-glucose sensing as a model system, using single-walled carbon nanotubes that modulate their emission in response to the adsorption of specific biomolecules. New types of non-covalent functionalization using electron-withdrawing molecules are shown to provide sites for transferring electrons in and out of the nanotube. We also show two distinct mechanisms of signal transduction - fluorescence quenching and charge transfer. The results demonstrate new opportunities for nanoparticle optical sensors that operate in strongly absorbing media of relevance to medicine or biology.